From 7de4f058f390460694093ec716a2e95958d05649 Mon Sep 17 00:00:00 2001
From: Harald Welte <laforge@osmocom.org>
Date: Fri, 15 Apr 2022 20:17:55 +0200
Subject: [PATCH] Add 'raw_prbs' handler to transmit a PRBS15 sequence

---
 Makefile        |  2 +-
 capi.c          |  1 +
 hdlr_raw_prbs.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 hdlr_raw_prbs.c

diff --git a/Makefile b/Makefile
index 35f9f5e..5c1071c 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,7 @@ clean:
 %.o: %.c
 	$(CC) $(CFLAGS) -o $@ -c $^
 
-capi-test: capi.o capiconn.o bchan.o hdlr_raw_loop.o
+capi-test: capi.o capiconn.o bchan.o hdlr_raw_loop.o hdlr_raw_prbs.o
 	$(CC) $(LDFLAGS) -o $@ $^ $(LIBS)
 
 
diff --git a/capi.c b/capi.c
index 38ce5c1..4a5fbe4 100644
--- a/capi.c
+++ b/capi.c
@@ -305,6 +305,7 @@ int main(int argc, char **argv)
 	osmo_init_logging2(ctx, &log_info);
 	capi_init(ctx);
 
+	bchan_route_add(-1, "142", "raw_prbs");
 	bchan_route_add(-1, NULL, "raw_loop");
 
 	while (1) {
diff --git a/hdlr_raw_prbs.c b/hdlr_raw_prbs.c
new file mode 100644
index 0000000..0eb6383
--- /dev/null
+++ b/hdlr_raw_prbs.c
@@ -0,0 +1,61 @@
+
+#include <osmocom/core/utils.h>
+#include <osmocom/core/prbs.h>
+
+#include "bchan.h"
+#include "errno.h"
+
+struct raw_prbs_priv {
+	struct osmo_prbs_state prbs;
+};
+
+static int raw_prbs_init(struct call_state *cst)
+{
+	struct raw_prbs_priv *rpp;
+	rpp = cst->priv = talloc_zero(cst, struct raw_prbs_priv);
+	if (!rpp)
+		return -ENOMEM;
+	osmo_prbs_state_init(&rpp->prbs, &osmo_prbs15);
+	return 0;
+}
+
+static void raw_prbs_rx(struct call_state *cst, const uint8_t *data, uint8_t len)
+{
+	struct raw_prbs_priv *rpp = cst->priv;
+	uint8_t tx_ubit[len*8];
+	uint8_t tx_pbit[len];
+	/* TODO: process what we received */
+
+	/* generate respective number of PRBS bits and transmit them */
+	osmo_prbs_get_ubits(tx_ubit, len, &rpp->prbs);
+	osmo_ubit2pbit(tx_pbit, tx_ubit, len*8);
+	bchan_call_tx(cst, tx_pbit, len);
+}
+
+static void raw_prbs_fini(struct call_state *cst)
+{
+	struct raw_prbs_priv *rpp = cst->priv;
+	talloc_free(rpp);
+	cst->priv = NULL;
+}
+
+
+static struct bchan_handler bch_raw_prbs = {
+	.name = "raw_prbs",
+	.cfg = {
+		.proto = { 1, 1, 0 },
+		.ncpi = NULL,
+		.max_b_data_blocks = 10,
+		.max_b_data_len = 32,
+	},
+	.ops = {
+		.init = raw_prbs_init,
+		.rx_data = raw_prbs_rx,
+		.fini = raw_prbs_fini,
+	},
+};
+
+static __attribute__((constructor)) void hdlr_raw_prbs_init(void)
+{
+	bchan_handler_register(&bch_raw_prbs);
+}